1. Field of the Invention
This invention relates to hand tools and, particularly, to adjustable end wrenches with means for effecting gross initial adjustment, and vice-locking means therefor to lock the jaws in position on and around a workpiece. In a preferred embodiment, the invention is disclosed as applied to a crescent-type adjustable wrench with improved simplified operation and construction.
2. Prior Art
The closest prior art known to applicant is that set forth in his prior patents, U.S. Pat. No. 3,190,154 issued June 22, 1965 for Adjustable End Wrench With Locking Means, and U.S. Pat. No. 3,333,492 similarly entitled and issued Aug. 1, 1967. Said prior patents disclose a wrench intended for the same purpose and providing more complex linkages for accomplishing a gripping of the workpiece under pressure with vice-like force. The instant invention accomplishes the same result in a more effective manner by more effectively, more simply and more economically positioning the clamping lever above and as part of the handle and operational therewith by the same turning movement as is utilized in turning the wrench handle in its normal and intended engagement with a workpiece as, for example, in turning a nut on a bolt, or, with suitably surfaced gripping jaws turning the smooth round bolt itself--in a manner of use heretofore reserved for conventional pipe wrenches or their like.
The number of parts are reduced and their shape and construction are simplified to eliminate complex linkages. Thus, simplified and economic manufacture results, and ease of use is also achieved.
Natural operation of the instant wrench corresponds to a wrench having a single handle. Its two-part handle automatically adjusts for increasing wrenching power. The gripping force becomes increasingly strong as the lever handle half is forced into its automatic gripping mode as required by the resistance of the workpiece. The full length of the single gripping lever acts more naturally and with improved leverage and mechanical advantage. It is to be noted that all of the known prior art calls for an initial hand-squeezing action around both the lever handle and the primary handle before the ultimate vice gripping is fully effective. The instant wrench can accomplish its gripping action, as well as its turning action, simultaneously because rotating and gripping action of the wrench are both transmitted through the lever which functions as a conventional handle to take up slack, and then when further pushed or pulled against the primary handle, the lever acts as a clamp handle, thus causing gripping of the jaws.